<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <title>求知家园</title>
        <style type="text/css">
            h3 {font-size:24px; color:red; text-align:center;}
        </style>
    </head>
    <body>
        <hr style="background-color:blue;;height: 2px;width:80%;">
        <center>
        	<h3>数学方程式</h3>
            <ul>
                <li>方程式1：2x2+3x=9</li>
                <li>方程式2：x1+x2=10</li>
            </ul>
        </center>
    </body>
</html>